Copco Lake is an artificial lake on the Klamath River in Siskiyou County, California, near the Oregon border in the United States. The lake's waters are impounded by the Copco Number 1 Dam (National ID CA00323), which was completed in 1922.[2] COPCO was an acronym referring to the California Oregon Power Company, which merged into Pacific Power and Light in 1961.[3]

Copco Number 2 Dam is a gated diversion dam located just below Dam No. 1. The dam diverts most of the flow of the river, about 2,400 to 2,500 cu ft/s (68 to 71 m3/s), through a flume and tunnels to a 27 megawatt powerhouse 1.5 miles (2.4 km) downstream, on the upstream end of Iron Gate Reservoir. The diversion bypasses a canyon section of the Klamath River that historically consisted of some steep rapids. The dam is required to maintain a minimum release of 10 cu ft/s (0.28 m3/s) to prevent this stretch from being entirely dewatered. Because it has no effective storage capacity, Dam No. 2 depends entirely on the regulated flows released from Copco Lake.[8]